System for simulated multi-gear vehicle sound generation

ABSTRACT

A vehicle sound generator system is configured to generate a signal configured to drive one or more speakers produce sound waves simulating sounds associated with a desired engine type. The signal is based on one or more operating conditions of a vehicle. The vehicle sound generator system is configured to select sounds from a plurality of sounds based on the operating conditions of the vehicle. Each sound corresponds to a simulated sound of an engine operating in a respective gear. The vehicle sound generator system may generate the signal to drive the speakers to produce selected sounds to simulate shifting between the respective gears.

PRIORITY CLAIM

This application is a continuation of PCT/US2010/053761, filed Oct. 22,2010, which claims the benefit of the filing date under 35 U.S.C.§119(e) of U.S. Provisional Patent Application No. 61/254,564, filedOct. 23, 2009, both of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Technical Field

The present disclosure relates generally to generating simulated vehiclesounds and, more particularly to, generating simulated sounds associatedwith operation of a multi-gear vehicle based on actual vehicle operatingconditions.

2. Related Art

Electric and hybrid vehicles are becoming increasingly popular due toenvironmental concerns and costs associated with fossil fuels and othercombustion fuels. However, electric vehicles typically may not havedesired characteristics found in combustion-engine vehicles. Among thosecharacteristics are the sounds associated with an engine acceleratingand shifting gears, either automatically or through manual control.Therefore, a need exists to provide simulated vehicle sound generationto provide a simulated audio experience of a desired vehicle type whileoperating another type of vehicle.

SUMMARY

A vehicle sound generator system may generate one or more signalsconfigured to drive speakers in a vehicle to produce simulated enginesounds. The vehicle sound generator system may generate signals based onoperating conditions of the vehicle. In one example, the signalsgenerated by the vehicle sound generator may drive the speakers toproduce simulated sounds of an engine operating in a respective gear.

The vehicle sound generator system may detect a change in the operatingconditions of the vehicle and select a different sound based on thedetected change. In one example, the vehicle sound generator may selecta sound based on changes in vehicle speed, vehicle throttle position, orboth. The vehicle sound generator system may detect operating conditionchanges based on one or more tables having predetermined operatingthresholds for the vehicle. The vehicle sound generator system maygenerate particular sounds corresponding to a particular gear of adesired engine when the operating conditions of the vehicle reach thepredetermined operating thresholds corresponding to the particular gear.

The vehicle sound generator system may be stored as one or more softwaremodules on a computer-readable medium or may be a combination ofhardware and software modules. The vehicle sound generator system may beexecutable by one or more processors. The vehicle sound generator systemmay select sounds from a sound library. The vehicle sound generatorsystem may be configured to generate signals to drive speakers orientedto produce sound waves into a cabin of the vehicle, outwardly from thevehicle, or both.

Other systems, methods, features and advantages of the invention willbe, or will become, apparent to one with skill in the art uponexamination of the following figures and detailed description. It isintended that all such additional systems, methods, features andadvantages be included within this description, be within the scope ofthe invention, and be protected by the following claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The system may be better understood with reference to the followingdrawings and description. The components in the figures are notnecessarily to scale, emphasis instead being placed upon illustratingthe principles of the invention. Moreover, in the figures, likereferenced numerals designate corresponding parts throughout thedifferent views.

FIG. 1 depicts a diagram of an example electric vehicle including asimulated vehicle sound generator system.

FIG. 2 depicts an example simulated vehicle sound generator system.

FIG. 3 depicts an example plot of pseudo engine speed versus road speedfor an electric vehicle.

FIG. 4 depicts an example simulated upshift table.

FIG. 5 depicts an example simulated downshift table.

FIG. 6 depicts an example operational flow diagram for the simulatedvehicle sound generator system of FIG. 2.

FIG. 7 is another example operational flow diagram for the simulatedvehicle sound generation system of FIG. 2.

FIG. 8 is another example operational flow diagram for the simulatedvehicle sound generation system of FIG. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIG. 1, a vehicle 100 is shown as including a simulated vehicle soundgenerator (SVSG) system 102. The vehicle 100 may include an audio system(AS) 104, shown in FIG. 1 as being located in a dashboard 106 of thevehicle 100. The audio system 104 may include various componentsassociated with a vehicle audio system such as AM/FM radio, CD player,cassette deck, personal music player input connector, equalizer,amplifier, cellular telephone interface, navigation system, and anyother components suitable for a vehicle audio system. The audio system104 may be two channel stereo or multi-channel, such as a five, six, orseven channel surround system. The audio system 104 may include softwaremodules, hardware modules, or a combination thereof used to processaudio signals provided to a plurality of speakers 105 throughout thevehicle 100. The audio system 104 may include a processor and a memorycapable of supporting the SVSG system 102, such as that described laterwith regard to FIG. 2.

In one example, the vehicle 100 may be a fully or partially-electricvehicle. The vehicle 100 may be driven by an electric motor 110. Inother examples, the vehicle 100 may include an internal combustionengine. The motor 110 of the vehicle 100 may generate sounds differentthan those that may be heard by vehicle occupants in other vehiclestypes, such as a vehicle having an internal combustion engine. Occupantsof an electric vehicle may desire to experience sounds associated withan internal combustion engine or other sound effect. The SVSG system 102may be configured to simulate sounds associated with a vehicle beingdriven by a combustion engine, such as a jet, motorboat, rocket, orother vehicle type. The SVSG system 102 may also be configured tosimulate other sounds as well. In one example, the SVSG system 102 maygenerate simulated engine sounds based on the operating condition of thevehicle 100, such as road speed and throttle position. For example, theSVSG system 102 may be configured to generate simulated soundsassociated with a vehicle having a multi-gear internal combustionengine. In one example, the vehicle 100 may include an internalcombustion engine. The SVSG system 102 may be configured to generatesimulated sounds to match the sounds of the internal combustion engineallowing the sound of the internal combustion engine experienced by alistener to be enhanced by the simulated sounds.

The sounds may be produced through speakers 105 present in the vehicle105. The speakers 105 may include a center (CTR) speaker, right front(RF) and left front (LF) speakers, right side (RS) and left side (LS)speakers, and right rear (RR) and left rear (LR) speakers as shown inFIG. 1. In one example, the vehicle 100 may also include a rightexternal (R EXT) and a left external (L EXT) speaker positioned in themotor compartment of the vehicle 100. Each of the speakers 105 may bedriven to produce sound waves based on audio signals generated by theSVSG system 102. The right and left external speakers may be driven toproduce simulated vehicle sounds that are audible outside/external tothe vehicle 100 and to occupants inside of the vehicle 100. In oneexample, sounds waves emitted by the external speakers may be used tovibrate portions of a motor compartment of the vehicle 100. In otherexamples, electromagnetic shaker panels may be used with the SVSG system102 to generate simulated engine sounds alone or in conjunction with thespeakers 105. This may provide a more realistic vehicle sound tooccupants in the vehicle 100 by producing simulated vehicle soundsassociated with vehicle components vibrating associated to withoperation of a desired engine type.

The SVSG system 102 may generate sounds based on various operatingconditions of the vehicle 100. For example, the SVSG system 102 mayreceive an input signal based on a throttle (T) 108 of the vehicle 100and road speed of the vehicle 100. “Road speed” may refer to a velocityrelated to a particular vehicle, including aircraft, watercraft, or anyother vehicle types. “Road speed” may also refer to a velocity ofwheeled vehicle regardless of whether the vehicle is travelling on road,off road, or some other non-road surface.

A position level of the throttle 108 may be provided directly to theSVSG system 102 as shown in FIG. 1 or may be indirectly obtained by theSVSG system 102 through a controlled area network (CAN) (not shown) orother suitable vehicle communication bus system. The road speed of thevehicle 100 may be determined at an instrumentation module 109 that maygenerate a road speed signal indicative of the road speed of the vehicle100. The SVSG system 102 may receive the throttle level of the throttle108 and the road speed signal. The SVSG system 102 may generatesimulated engine sounds based on the throttle level and the road speedsignal. In other examples, one or more other input signals may beutilized in addition to or in lieu of the throttle position and roadspeed, such as motor load, torque, power, vehicle light status, orcruise control operation.

The vehicle 100 may also include an input device (ID) 114. The inputdevice 114 may include a manual gear shifter allowing a vehicle occupantto manually provide input to the SVSG system 102 indicating when asimulated upshift or downshift is desired. The input device 114 may beused in conjunction with automatic simulated multi-gear functions,allowing the SVSG system 102 to operate in a semi-automatic manner. Inone example, the input device 114 may be a lever mounted in a steeringcolumn of the vehicle 100, dash board 106, or in another appropriatearea within the vehicle 100. In other examples, the input device 114 mayinclude multiple levers, or other mechanisms configured to receivemanual input, disposed within the vehicle 100, such as separatededicated upshift or downshift levers. Levers or other devices may bemulti-positional allowing a particular simulated gear to have a specificposition. In other examples, the levers may be of a “slap-shift”configuration allowing the levers to be biased from an initial positionfor simulated downshifting/upshifting and returning to the initialposition for subsequent simulated shifting.

The SVSG system 102 may be implemented within the audio system 104 asshown in FIG. 1 or may be implemented as a stand-alone system separatefrom the audio system 104. The SVSG system 102 may produce audible soundthrough one more of the speakers 105, which may be shared with the audiosystem 104 or strictly dedicated to the SVSG system 102. Alternatively,additional speakers 105 may be added to those shown in FIG. 1 to usewith the SVSG system 102. The SVSG system 102 may select a subset ofavailable speakers 105 to generate desired simulated engine sound basedon input from a current vehicle occupant or based on predeterminedcriteria. For example, a first driver of the vehicle 100 may desire thatthe left and right external and the center speakers be used to producesounds from the SVSG system 102. A second subsequent driver of thevehicle 100 may desire that only the center speaker be used to producesounds from the SVSG system 102 and select such a speaker configuration.In one example, the SVSG system 102 may include and/or be incommunication with a user interface, such as graphical user interface(GUI) 112 on board the vehicle to allow the particular speakerselections, sound effects, etc., to be selected by an occupant of thevehicle 100. The GUI 112 may be integrated to control various aspects ofthe vehicle 100 such as the audio system 104, environmental controls,etc.

FIG. 2 is a block diagram of the SVSG system 102, such as that describedin FIG. 1. The SVSG system 102 may include a computer device 200 havinga memory 202 and a processor 204. The memory 202 may include one or morememories and may be computer-readable storage media or memories, such asa cache, buffer, RAM, removable media, hard drive or other computerreadable storage media. Computer readable storage media may includevarious types of volatile and nonvolatile storage media. Variousprocessing techniques may be implemented by the processor 204 such asmultiprocessing, multitasking, parallel processing and the like, forexample. The processor 204 may include one or more processors. Thecomputer device 200 may be included in the audio system 104 as describedwith regard to FIG. 1 or may be a stand-alone device in addition to theaudio system 104.

The processor 204 may execute a simulated vehicle sound generator module206 included in the SVSG system 102. As described herein, the term“module” may be defined to include software, hardware or somecombination thereof executable by the processor 204. Software mayinclude instructions stored in the memory 202, or other memory device,that are executable by the processor 204 or other processor. Hardwaremay include various devices, components, circuits, gates, circuitboards, and the like that are executable, directed, and/or controlledfor performance.

The computer device 200 may receive input signals from various sensorsor other sources based on operating conditions of the vehicle 100. InFIG. 2, the computer device 200 may receive a throttle level signal 210from the throttle 108 and a road speed signal 212 from theinstrumentation module 109. The computer device 200 may also generate aplurality of simulated sound signal 214 that may be used to producesounds through driving the speakers 105. Each simulated sound signal 214is individually designated as SS1 through SSN in FIG. 2, where N is thenumber of speakers 105 that may receive a simulated sound signal 214.

The simulated vehicle sound generator module 206 may receive input fromthe GUI 112 indicating a user-selected parameter related to theparticular sounds desired, such as a particular make/model of anautomobile, a jet, rocket, spacecraft, etc., or a non-vehicle soundeffect. A user may select the desired sound effect from a plurality ofsound effects stored in a sound library data set 216 stored in thememory 202. The sound library data set 216 may be updated to add othersound effects or to update current sound effects through the GUI 112,wireless communication, wired communication, or any other manner ofcommunicating update information to the computer device 200.

In one example, the simulated vehicle sound generator module 206 may beconfigured to generate simulated sounds signals to include simulatedgear shifting and operation in a particular gear for a simulated enginetype based on the operating conditions of the vehicle 100. The simulatedgear shifting may refer to simulation associated with operation of ageared engine found in various vehicles having combustion engines, whichmay include upshifting, i.e., transitioning from a current gear to ahigher gear, and downshifting, i.e., transitioning from a current gearto a lower gear.

Based on the throttle signal 210 and the road speed signal 212, thesimulated vehicle sound generation module 206 may generate soundsassociated with operating vehicle such as accelerating and deceleratingin multiple simulated gears along with upshifting and downshifting intothe gears. The simulated vehicle sound generator module 206 may access ashift table data set 218 stored in the memory 202. Sounds associatedwith simulated gear shifting may be based on the actual road speed ofthe vehicle 100 and the throttle position of the throttle 108. Use ofthe simulated gear shifting may provide an occupant of the vehicle 100 aricher experience associated with simulated engine sounds associatedwith a particular vehicle type.

The sound library 216 may be configured to store information regardingsimulated sounds for particular engine types. The sounds may be storedas information for each engine type that may be implemented by the SVSGmodule 206 to generate the simulated sounds signal 214. In one example,the sounds may be stored in the sound library 216 as sound information(“SI”) 219 related to sound measurements taken for particular enginetypes. Sound measurements for particular engine types may be taken froman actual engine of the particular type and analyzed to determinevarious sound characteristics, such as the dominant harmonics of aparticular engine type, as well as, other sound characteristicsassociated with the particular engine type. These sound measurements maybe processed into data represented by the sound information 219 that maybe used by the SVSG module 206. In one example, the SVSG module 206 mayimplement a synthesizer module (“SM”) 207, which allows the SVSG module206 to generate a simulated sound signal 214 based on the soundinformation 219 stored in the sound library 216.

The sound library 216 may include a look-up table mapping soundinformation associated with sounds for each available engine type tocorresponding operating conditions of the vehicle 100. For example, thesound information 219 may be stored digitally so that a particularportion of the sound information 219 corresponds to particular operatingconditions of the vehicle 100. The SVSG module 206 may then receive thesignals 210, 212, and/or 213 from the throttle 108, instrumentationmodule 109, and input device 114, respectively, and based on the signals210, 212, and/or 213, retrieve the corresponding sound information 219from the sound library 216 to synthesize the simulated sound signal 214.As the vehicle 100 changes in speed, the SVSG module 206 may manipulatethe simulated sound signal 214 to drive the speakers 105 to produce thedesired simulated engine sound. The SVSG module 206 may also implementthe shift table 218 in adjusting the simulated sounds signals 214 toproduce the desired sounds through the speakers 105.

The SVSG module 206 may also monitor the differential of the vehiclespeed, which may serve as a proxy for the throttle position of thethrottle 108 and load of the motor 110 in a fully-electric or hybridvehicle 100. Based on the differential, the SVSG module 206 maydetermine the amount energy regeneration occurring in the motor 110. Inone example, the motor 110 may perform regenerative braking in order toslow the vehicle 100. The SVSG module 206 may use the current generatedby the motor 110 during regenerative braking to determine that thevehicle is decelerating. For example, the SVSG module 206 may retrievesound information 219 from the sound library 216 corresponding to thelevel of regenerative braking current and generate the simulated soundsignal 214 based on the retrieved sound information 219. The simulatedsound signal 214 may drive the speakers 105 to produce sounds associatedwith engine braking of the particular engine type being simulated. Thus,sounds produced by the speakers 105 may also provide an audio indicationof the level of regenerative braking taking place to a listener.

FIG. 3 shows an example of a plot representative of simulated upshiftand downshift threshold points with respect to the road speed of thevehicle 100. The plot 300 plots the road speed (R) of the vehicle 100versus a pseudo engine speed (rpm) of the vehicle 100. The pseudo enginespeed may provide a reference number representing calculated revolutionsper minute associated with a simulated engine based the actual roadspeed of the vehicle 100.

In FIG. 3, a pseudo engine speed versus road speed plot is generated forsix different simulated gears, individually designated as G1 through G6for FIG. 3. In other examples, any number of gears may be used. Thepseudo road speed may be calculated using the equation:E _(n) =R/G _(n)  Eqn. 1where E_(n) is the pseudo engine speed, R is the actual road speed ofthe vehicle 100, and G_(n) is the effective gear ratio. The subscript“n” represents the particular gear number. Since G_(n) is a constant foreach gear, the resultant road speed v. pseudo engine speed plot for eachgear produces a straight line as shown in FIG. 3. In one example, thesimulated gear ratios for six simulated gears may be as shown in Table1:

TABLE 1 Gear G_(n) G1 1 G2 0.6 G3 0.44 G4 0.35 G5 0.3 G5 0.25

The plot of FIG. 3 illustrates where various upshift and downshiftthreshold points that may be set with regard to the road speed of thevehicle 100. In FIG. 3, the downwardly pointing arrows 302 connectingadjacent plot lines for each gear represent a lowest speed in theparticular simulated gear where a simulated upshift to the next gear,e.g. G1 to G2, may occur. The upwardly pointing arrows 304 may representthe highest road speed for the particular gear at which the arrow headterminates that a downshift may occur into that particular gear.

While the plot of FIG. 3 illustrates road speed thresholds for simulatedupshifting and downshifting for various road speeds of the vehicle 100,the simulated vehicle sound generator module 206 may also rely on thethrottle position of the throttle 108 to select the proper simulatedgear sound to be produced through the speakers 105. In one example,various throttle position threshold points of the throttle 108 may bepredetermined for use by the simulated vehicle sound generator module206. For example, a minimum throttle position, T_(min), may be selectedto be about 10% or less of the full throttle position and a maximumthrottle position, T_(max), may be selected as about 90% or more of thefull throttle position. The sounds associated with the simulated gearsincluding sounds associated operating an engine in the particular gears,as well as upshifting and downshifting into the particular gears, may begenerated based on a current road speed and the throttle position of thevehicle 100.

When synthesizing the simulated engine sounds or using recorded soundsfrom the sound information 219, the SVSG module 206 may implement theshift table 218 in order to accurately produce the simulated sounds asdesired. The SVSG module 206 may adjust the simulated sound signal 214using the signals 210, 212, and 213 as described with regard to FIG. 3.During adjustment, the SVSG module 206 may also implement the shifttable 218 as well, allowing the SVSG module 206 to generate the desiredsound for the desired simulated gear.

In some actual internal combustion engines, transitions between gearsduring shifting may not be substantially instantaneous due to theinertia of mechanical components involved in the gear transition. In oneexample, the SVSG module 206 may generate the simulated sound signal 214to drive the speakers 105 to produce sounds associated with geartransitions of such nature. The SVSG module 206 may generate soundsassociated with “overshoots” and “undershoots” depending on the currentoperating conditions of a vehicle. For example, an “overshoot” may referto a situation in which a driver has engaged a clutch and is alsoengaging throttle causing the engine speed to rapidly increase due tothe clutch being engaged by the driver. An “undershoot” may refer to theclutch being engaged with no throttle being operated causing the enginespeed to rapidly drop. Based on the signals 210, 212, and 213, the SVSGmodule 206 may determine that such conditions are present to generatethe simulated sound signal 214 to simulate sounds associated withovershoot and undershoot when the simulated gears are shifted. In oneexample, the SVSG module 206 module may generate the simulated soundsignal 214 to drive the speakers 105 to produce the appropriate soundfor overshoot or undershoot for a predetermined period of time.

The SVSG module 206 may allow adjustment of various parameters used toproduce the simulated sounds signal 214. For example, the SVSG module206 may provide an interface through the GUI 112 to receive input foradjustment of the gear ratios. Each virtual gear may be adjusted so thata particular ratio may be input. The SVSG module 206 may also allowadjustment of the minimum and maximum pseudo-engine speed through theGUI 112. The SVSG module 206 may also allow the upshift and downshiftthreshold points for each simulated gear to be adjusted to desired roadspeeds through the GUI 112. The SVSG module 206 may allow input to bereceived for adjustment of a time interval over which the demanded speedis reached for each simulated gear through the GUI 112. This may includean acceleration ramp and deceleration ramp for each simulated gear. TheSVSG module 206 may generate the simulated sound signal 214 used toproduce sounds associated with the acceleration over the accelerationramp and deceleration over the deceleration ramp during the selectedtime intervals, respectively.

FIG. 4 is an example of a simulated upshift table 400 and FIG. 5 is anexample of a simulated downshift table 500 that may each be included inthe shift table data set 218 stored in the memory 202. The simulatedupshift table 400 shows the upshifting for simulated gears G1 throughG5. The simulated vehicle sound generator module 206 may generatesimulated sound signal 214 associated with a particular simulated gearG1 through G6 and associated with the upshift of into each simulatedgear. The simulated vehicle sound generator module 206 may be configuredto generate a simulated sound signal 214 representing an upshift toproduce a sound by driving a speaker 105 to produce sounds wavesassociated with simulated operation in the next highest gear based onthe simulated upshift table 400. In one example, each simulated gearother than the highest simulated gear G6, may include a first upshiftthreshold point and a second upshift threshold point. For example, inthe simulated upshift table 400, the sounds associated with the firstsimulated gear G1 will be produced until the road speed is greater thanR₁ and the throttle position is less than T_(max). If these conditionsexist, sounds associated with an upshift into the second simulated gearG2 will be generated to produce simulated engine sounds associated withoperating in the second simulated gear G1. This range of throttleposition and road speed may be selected to allow the simulatedupshifting to occur during operation of the vehicle 100 that may occurunder similar road speeds and engine speeds associated with an internalcombustion engine or other engine type.

If the throttle 108 is quickly depressed and is greater than T_(max)before the road speed reaches R₂, the simulated upshifting to G2 may bebypassed until the road speed reaches R₄. This configuration allows theaudio experience associated with simulated upshifting from the firstsimulated gear G1 to the second simulated gear G2 to also occur when theroad speed is greater than R₄ and the throttle position is greater thanor equal to T_(max). Simulated upshifting at this range of road speedsand throttle position may provide the simulated audio experienceassociated with sounds generated from quickly pressing down on theaccelerator of a vehicle having a combustion engine, which may drive upthe engine speed without immediately shifting into the next gear. Thesimulated upshift table 400 includes similar simulated upshiftingconditions for the other simulated gears G2 through G5.

The simulated downshifting table 500 may also be accessed by thesimulated vehicle sound generator module 206 during operation of thevehicle 100. The simulated downshifting table 500 may be including inthe shifting table data set 218. The simulated downshifting may occurfrom each current simulated gear to any other lower simulated geardepending on the road speed of the vehicle 100 and the throttle positionof the throttle 130. The simulated downshifting table 500 may includesimulated downshifting conditions from each gear G2 to G6 to eachrelative lower gear. For example, the sixth simulated gear G6 maydownshift to each of the gears G5 to G1. Downshifting from the sixthgear to any of the other gears may depend on the road speed R and thethrottle position T. The simulated downshifting table 500 includessimilar operating condition resulting in simulated downshifting for eachof the other simulated gears G2 through G5.

While the road speed is greater than zero, no simulated downshifting mayoccur while the throttle position is less than T_(min). This may producethe experience associated with a vehicle that is coasting with noaccelerator input, which will fail to downshift even with a decreasingroad speed until the accelerator is reapplied to some degree. Thedownshifting threshold points are selected to be different from theupshifting threshold points to avoid toggling between simulated gears ifthe vehicle operates about a particular road speed for a substantialamount of time causing shared threshold points to result in frequenttoggling between simulated gears.

In an alternative example, the SVSG module 206 may utilize a set ofequations to generate the simulated sounds signal 214. The equations maybe stored in the memory 202 and implemented by the SVSG module 206. Insuch a configuration, the SVSG module 206 may periodically updatevariables in the set of equations based on various current operatingconditions of the vehicle 100 as input, such as road speed and throttleposition. The SVSG module 206 may control the simulate sounds signal 214based on the updated values of the set of equations. Particularequations may be dedicated to determining upshift and downshiftthreshold points, such that particular values of these equations mayindicate when the SVSG module 206 should manipulate the simulated soundsignal 214 to simulate upshiftng and downshifting sounds. Particularequations may also be dedicated to indicating that simulated overshootor undershoot conditions may be present allowing the SVSG module 206 tomanipulate the simulated sound signal 214 accordingly.

FIG. 6 is an operational flow diagram for generating sounds using thesimulated vehicle sound generator module 206 for a six-speed simulatedengine. At block 600, the simulated vehicle sound generator module 206may begin to generate simulated sound signal 214 associated with thefirst simulated gear G1. At block 602, the SVSG module 206 may determineif a first upshift condition (UC11) for simulated gear G1 is present.For example, as discussed with regard to FIGS. 3-5, one upshiftcondition may be a road speed of the vehicle 100 above a first roadspeed threshold point, such as road speed R₁, and the throttle positionbeing between T_(min), and T_(max). If such a condition is present, thesimulated vehicle sound generator module 206 may generate soundsassociated with an upshift to the second simulated gear G2. If the firstupshift conditions are not present, at block 604, the simulated soundgenerator module 206 may determine if a second upshift condition (UC12)is present. In one example, the second upshift condition may be a roadspeed greater than R₄ and a throttle position greater than T_(min). Ifthese conditions are present, the simulated vehicle sound generatormodule 206 may generate simulated sound signal 214 associated withshifting into and operating in the second simulated gear G2.

While operating in the second simulated gear G2, at block 608 thesimulated vehicle sound generator module 206 may determine if a firstupshift condition (UC21) is present for G2, such as the road speed beinggreater than R₃ and the throttle position being less than T_(max). Ifthe first upshift condition is present, the simulated vehicle soundgenerator module 206 may generate sounds associated with shifting intoand operation of the third simulated gear G3. If the first upshiftcondition is not present, the simulated sound generator module maydetermine the second upshift (UC23) condition is present, such as theroad speed being greater than R₁₀ and the throttle position beinggreater than or equal to T_(max). If the second upshift condition ispresent, the simulated vehicle generator module 206 may generate soundsassociated with upshifting to and operation of the third simulated gearG3.

If neither of the upshift conditions of the second simulated gear G2 ispresent, at block 612, the simulated vehicle generator module 206 maydetermine if a downshift condition (DS G1) is present to downshift tothe first simulated gear G1. In one example, the simulated soundgenerator module 206 may determine if the road speed is less than R₂ andthe throttle is between T_(min) and T_(max). If the throttle position isless than or equal to T_(min), the vehicle 100 may be in a “coast”condition representing a relatively small amount of throttle beingapplied. If the coast condition is present, the simulated vehicle soundgenerator module 206 may not generate sounds associated withdownshifting into the first simulated gear G1. If the downshiftcondition is present at block 612, at block 614 the simulated vehiclesound generator module 206 may generate sounds associated withdownshifting into the first simulated gear G1, and the simulated soundgenerator module 206 may continue to generate sounds associated withoperating in the first simulated gear G1, while continuing to monitorfor the presence of the upshift conditions UC11 and UC12.

While operating in the third simulated gear G3, at block 618 thesimulated vehicle sound generator module 206 may determine if a firstupshift condition (UC31) is present for G3, such as the road speed beinggreater than R₆ and the throttle position being less than T_(max). Ifthe first upshift condition is present, at block 622 the simulatedvehicle sound generator module 206 may generate simulated sound signalassociated with shifting into and subsequently operation of the fourthsimulated gear G4. If the first upshift condition is not present, atblock 620 the simulated vehicle sound generator module 206 may determineif a second upshift condition (UC32) is present, such as the road speedbeing greater than R₁₂ and the throttle position being greater than orequal to T_(max). If the second upshift condition is present, at block622 the simulated vehicle sound generator module 206 may generate soundsassociated with upshifting to and subsequent operation in the fourthsimulated gear G4.

If none of the upshift conditions are present for the third simulatedgear G3, the simulated vehicle sound generator module 206 may determineif downshift conditions are present. The simulated downshift conditionsmay be based on the road speed of the vehicle 100 and the current roadspeed of the vehicle 100 may determine the particular simulated gearsounds to generate through the simulated vehicle sound generator module206. At block 612, the determination for downshifting may be made by thesimulated vehicle sound generator module 206 in manner previouslydiscussed. If the conditions for downshifting to the first simulatedgear G1 are present, the simulated vehicle sound generator module 206may produce simulated sound signal 214 associated with the downshiftinto and operation of the first simulated gear G1. However, the roadspeed may be higher than the simulated downshift threshold speed for thevehicle 100, but may be appropriate for downshifting to the secondsimulated gear G2. At block 624, the determination is made by thesimulated vehicle sound generator module 206 if downshifting conditions(DS G2) to the second simulated gear G2 are appropriate. In one example,these conditions may be a road speed of great than or equal to R₂ andless than R₅ and a throttle position between T_(min) and T_(max). If thesimulated downshift conditions are present, at block 625 the simulatedvehicle sound generator module 206 may adjust the sounds being producedto those of shifting to the second simulated gear G2 and return toproducing simulated sounds signals 214 representative of operation inthe second simulated gear G2.

While operating in the fourth simulated gear G4, at block 626 thesimulated vehicle sound generator module 206 may determine if a firstupshift condition (UC41) is present for G4, such as the road speed beinggreater than or equal to R₇ and the throttle position less than T_(max).If the first upshift condition is present, at block 630, the simulatedvehicle sound generator module 206 may generate simulated sound signalassociated with shifting into and operation of the fifth simulated gearG5. If the first upshift condition is not present, at block 628 thesimulated vehicle sound generator module 206 may determine if a secondupshift condition (UC32) is present, such as the road speed beinggreater than R₁₄ and the throttle position being greater than or equalto T_(max). If the second upshift condition is present, at block 630 thesimulated sound generator module may generate simulated sound signal 214associated with upshifting to and operation of the fifth simulated gearG5.

If the simulated upshift conditions for the fourth simulated gear G4 arenot present, the simulated vehicle sound generator module 206 maydetermine if simulated downshift conditions are present. The simulatedvehicle sound generator module 206 may determine if conditions fordownshifting to the first simulated gear G1 and second simulated gear G2are present at blocks 612 and 622, respectively. If presence of one ofthe conditions is detected, the appropriate simulated sound signal 214may be generated for downshifting into the particular simulated gear maybe produced by simulated vehicle sound generator module 206. If theconditions are not present, at block 632 the simulated vehicle soundgenerator module 206 may determine if simulated downshifting conditions(DS G3) to the third simulated gear G3 exist. In one example, theconditions may be the road speed being greater than or equal R₅ and lessthan R₈ and the throttle level being between T_(min) and T_(max). If theconditions are present, at block 634, the simulated vehicle soundgenerator module 206 may generate sounds associated with downshifting tothe third simulated gear G3. If the conditions are not present, thesimulated vehicle sound generator module 206 may continue producingsounds associated with the third simulated gear G3.

While producing sounds associated with operating in the fifth simulatedgear G5, at block 636 the simulated vehicle sound generator module 206may determine if a first upshift condition (UC51) is present for G5,such as the road speed being greater than or equal to R₉ and thethrottle position being less than T_(max). If the first upshiftcondition is present, at block 640 the simulated vehicle sound generatormodule 206 may generate simulated sound signal 214 associated withshifting into and operation of the sixth simulated gear G6. If the firstupshift condition is not present, at block 638 the simulated soundgenerator module 206 may determine if a second upshift condition (UC52)is present, such as the road speed being greater than R₁₅ and thethrottle position being greater than or equal to T_(max). If the secondupshift condition is present, at block 640 the simulated vehicle soundgenerator module 206 may generate simulated sound signal 214 associatedwith simulated upshifting to operation of the sixth simulated gear G6.

The simulated vehicle sound generator module 206 may also determine ifsimulated downshifting may occur while producing sounds associated withoperating in the fifth simulated gear G5. In one example, the simulatedvehicle sound generator module 206 may determine if sounds associatedwith downshifting to the first, second, and third simulated gears shouldoccur similar to that previously described. In none of the conditionsare present, at block 642 the simulated vehicle sound generator module206 may determine if downshifting conditions (DS G4) are present fordownshifting to the fourth simulated gear G4. In one example, theseconditions may be a road speed greater than or equal to R₈ and less thanR₁₁ and the throttle position between T_(min) and T_(max). If theconditions are present, at block 644 the simulated vehicle soundgenerator module 206 may generate simulated sound signal 214 associatedwith downshifting into the fourth simulated gear G4 and may continuegenerating simulated sound signal 214 associated with operating thefourth simulated gear G4. If the downshifting conditions are notpresent, the simulated vehicle sound generator module 206 may continuegenerating simulated sound signal 214 associated with operating in thefifth simulated gear G5.

While producing sounds associated with operating in the sixth simulatedgear G6, the simulated vehicle sound generator module 206 may determineif downshifting to the lower simulated gears is appropriate. Thesimulated vehicle sound generator module 206 may determine if simulateddownshifting is appropriate for each of the simulated gears G1 throughG4 as previously described. If the conditions for downshifting intothese gears do not exist, at block 646 the simulated vehicle soundgenerator module 206 may determine if conditions (DS G5) exist fordownshifting into the fifth simulated gear G5. In one example, theseconditions may be a road speed less than or equal to R₁₁ and greaterthan R₁₃ a throttle position between T_(min) and T_(max). If theconditions are present, the simulated vehicle sound generator module 206may generate sounds associated with simulated downshifting into thefifth simulated gear G5 and continue producing sounds associated withoperating in the fifth simulated gear G5. If the conditions are notpresent, the simulated vehicle sound generator module 206 may continuegenerating simulated sound signal 214 associated with operating in thesixth simulated gear G6.

The operational flow diagram of FIG. 6 may be configured to includeadditional or fewer gears than that described. Furthermore, theparticular simulated upshift and downshift conditions may be altered,removed, or replaced for particular implementations of simulated vehiclesound generator module 206. The particular upshift and downshiftthresholds may be user-adjusted through input received by through theGUI 112. In one example, the SVSG system 102 may include various optionssuch as simulated vehicle selection, which may modify the gear rationsG_(n) used to determine the rate to increase or decrease simulatedsounds intensity regarding the road speed of the vehicle 100. Otherinput parameters may include simulated manual or automatic transmission.Adjustment of such features may alter the simulated sound signal 214 foreach simulated gear allowing a vehicle occupant to achieve a desiredsound experience associated with the SVSG system 102.

FIG. 7 is another operational flow diagram for generating simulatedmulti-gear vehicle sounds using the SVSG system 102. At block 700, thesimulated sound parameters may be determined. In one example, thesimulated sound parameters may include various vehicles characteristicsincluded in the sound library data set 216. A user may select aparticular vehicle type with particular characteristics through the GUI112. The selected parameters may be received by the simulated vehiclesound generation module 206 in order to determine the appropriatesimulated sounds signals 214 to generate.

At block 702, generation of the simulated vehicle sounds may begin inthe lowest simulated gear G1. During operation, various operatingconditions associated the vehicle 100 may be monitored such as roadspeed and throttle position. At block 704, the simulated vehicle soundgeneration module 206 may determine if an upshift condition is present.Various upshift conditions may be used, such as those described withregard to the simulated upshift table 400. If no upshift condition ispresent, the simulated vehicle sound generation module 206 may continuegeneration simulated sound signal 214 associated with the firstsimulated gear G1. If the upshift condition is present, at block 706 thesimulated vehicle sound generation module 206 may generate simulatedsound signal 214 associated with the next highest gear, G2. Duringgeneration of the simulated sounds signals 214 for the second simulatedgear G2, at block 708 the simulated vehicle sound generation module 206may determine if another upshift condition is present. If anotherupshift condition is present, at block 706 the simulated vehicle soundgeneration module 206 may begin generating simulated sound signalassociated with the next highest gear.

If the upshift condition is not present at block 708, at block 710simulated vehicle sound generation module 206 may determine if adownshift condition is present. The downshift conditions may bepredetermined such those discussed with regard to the simulateddownshift table 500, for example. If downshift conditions are notpresent, the simulated vehicle sound generation module 206 may continuegenerating simulated sounds signals 214 for the current simulated gear.If the downshift conditions are present, at block 712 simulated vehiclesound generation module 206 may determine the appropriate gear to whichto downshift based on conditions such as those in the simulateddownshift table 500. Upon determination of the appropriate simulatedgear, at block 714 the simulated vehicle sound generation module 206 maygenerate simulated sound signal 214 associated with the determined lowergear.

At block 716, simulated vehicle sound generation module 206 maydetermine if the vehicle 100 has stopped resulting in a road speed ofzero. If the vehicle has stopped, the simulated vehicle sound generationmodule 206 may begin generation of the simulated sounds signals 214 forthe first simulated gear G1. If the road speed is not zero, simulatedvehicle sound generation module 206 may continue generating simulatedsound signal for the current simulated gear selected. The operationalflow diagram of FIG. 7 may continue to operate until the SVSG system 102is deactivated by a vehicle occupant or the vehicle is power off.

The operational flow diagram of FIG. 7 may be used in conjunction withthe operation flow diagram of FIG. 6. In one example, the six simulatedgears of the operation flow diagram of FIG. 6 may be configured to be asubset of the operational flow diagram of FIG. 7.

FIG. 8 is another operational flow diagram operational flow diagram forgenerating simulated multi-gear vehicle sounds using the SVSG system102. The operational flow diagram of FIG. 8 is similar to that of FIG.7. In FIG. 8, if an upshift condition is present (block 708) adetermination (block 800) may be made regarding throttle engagement. Ifthe throttle 108 of the vehicle 100 is engaged, sound associated withengine overshoot may be generated (block 802) prior to the simulatedsound for the next highest gear being generated (block 706). If thethrottle 108 is not engaged, sounds associated with engine undershootmay be generated (block 804) prior to the simulated sound for the nexthighest gear being generated (block 706).

If a downshift condition is determined to be present and a lower gear isdetermined (block 712), a determination may be made regarding thethrottle engagement (block 800). If the throttle is engaged, soundassociated with engine overshoot may be generated (block 802) prior tothe simulated sound for the determined lower gear (block 712). If thethrottle 108 is not engaged, a determination may be made regarding ifmotor regeneration is present (block 806). If motor regeneration ispresent, simulated sounds associated with engine braking may begenerated (block 808) prior to simulated sounds for the determined lowergear being generated (block 714). If regeneration is not present,simulated sounds associated with engine braking may be generated (block810) prior to simulated sounds for the determined lower gear beinggenerated (block 714).

While various embodiments of the invention have been described, it willbe apparent to those of ordinary skill in the art that many moreembodiments and implementations are possible within the scope of theinvention. Accordingly, the invention is not to be restricted except inlight of the attached claims and their equivalents.

We claim:
 1. A simulated vehicle sound generator system for a vehicle, the system comprising: a memory configured to store sound information for each of a plurality of predetermined engine types; a processor in communication with the memory; and a simulated vehicle sound generation module executable by the processor to: receive a signal indicative of an operating condition of the vehicle; retrieve sound information for one of the plurality of predetermined engine types in response to the operating condition of the vehicle; select a first simulated gear from a plurality of simulated gears in response to the operating condition of the vehicle; generate a sound signal corresponding to a first operating range of the first simulated gear based on the retrieved sound information, the sound signal configured to drive at least one sound generation device to produce variable sound waves to simulate operation of the one of the plurality of predetermined engine types along the first operating range of the first simulated gear; determine a shift condition in response to an operating condition indicative of a speed of the vehicle reaching a variable threshold point corresponding to the first simulated gear, the variable threshold point being variable based on an operating condition indicative of a load of the vehicle; select a second simulated gear from the plurality of simulated gears in response to the determined shift condition; and adjust the sound signal in response to the determined shift condition to correspond to a second operating range of the second simulated gear, the sound signal adjusted to drive the at least one sound generation device to produce variable sound waves to simulate operation of the one of the plurality of predetermined engine types along the second operating range of the second simulated gear.
 2. The simulated vehicle sound generator system of claim 1, where the simulated vehicle sound generation module is further executable to synthesize the sound signal in response to the retrieved sound information, where the synthesized sound signal includes a dominant harmonic frequency associated with operation of the one of the plurality of predetermined engine types in the first simulated gear.
 3. The simulated vehicle sound generator system of claim 1, where the simulated vehicle sound generation module is further executable to synthesize the sound signal in response to the retrieved sound information, where the sound information is associated with recorded sounds from the one of the plurality of predetermined engine types.
 4. The simulated vehicle sound generator system of claim 1, where the simulated vehicle sound generation module is further executable to drive the at least one sound generation device to produce variable sound waves to simulate a gear transition from the first simulated gear to the second simulated gear in response to the determined shift condition and the operating condition indicative of the load of the vehicle.
 5. The simulated vehicle sound generator system of claim 1, where the operating condition indicative of the speed of the vehicle comprises at least one of a road speed and a pseudo engine speed, and where the operating condition indicative of the load of the vehicle comprises at least one of a throttle position, a motor load, and a torque.
 6. The simulated vehicle sound generator system of claim 1, where the simulated vehicle sound generation module is further executable to determine the shift condition in response to the operating condition indicative of the a speed of the vehicle exceeding the variable threshold point corresponding to the first simulated gear at a current value of the operating condition indicative of the load of the vehicle, the shift condition being an upshift condition, where the second simulated gear is higher than the first simulated gear.
 7. The simulated vehicle sound generator system of claim 1, where the variable threshold point corresponding to the first simulated gear increases with increasing throttle position up to a maximum threshold value at a maximum throttle position, and where the variable threshold point corresponding to the first simulated gear decreases with decreasing throttle position down to a minimum threshold value at a minimum throttle position.
 8. The simulated vehicle sound generator system of claim 1, where the simulated vehicle sound generation module is further executable to determine the shift condition when the operating condition indicative of the speed of the vehicle is within a predetermined vehicle speed range and the operating condition indicative of the load of the vehicle is within a load range, the shift condition being a downshift condition, where the second simulated gear is lower than the first simulated gear.
 9. The simulated vehicle sound generator system of claim 8, where the simulated vehicle sound generation module is further executable to bypass determination of the shift condition and select the second simulated gear in response to the operating condition indicative of the speed of the vehicle being greater than zero and the operating condition indicative of the load of the vehicle being less than a minimum value.
 10. The simulated vehicle sound generator system of claim 1, where the at least one sound generation device comprises a first loudspeaker configured to project sound waves directed into a cabin of the vehicle and a second loudspeaker configured to project sound waves outwardly from the vehicle.
 11. The simulated vehicle sound generator system of claim 1, where the at least one sound generation device comprises a loudspeaker.
 12. The simulated vehicle sound generator system of claim 1, where the at least one sound generation device comprises an electromagnetic shaker panel.
 13. The simulated vehicle sound generator system of claim 1, where the simulated sound generation module is further executable to receive a signal indicative of a user input and adjust the first operating range of the first simulated gear based on the received signal.
 14. The simulated vehicle sound generator system of claim 1, where the simulated sound generation module is further executable to receive a signal indicative of a user input and adjust the variable threshold point corresponding to the first simulated gear based on the received signal.
 15. The simulated vehicle sound generator system of claim 1, where the simulated vehicle sound generation module is further executable to: receive a gear shift signal from a manual input device of the vehicle; retrieve sound information corresponding to the gear shift signal; and determine the shift condition in response to the received gear shift signal.
 16. The simulated vehicle sound generator system of claim 1, where the simulated vehicle sound generation module is further executable to: determine a differential of the operating condition of the vehicle; retrieve sound information for the one of the plurality of predetermined engine types corresponding to the operating condition indicative of the speed of the vehicle and the differential of the vehicle; and adjust the sound signal based on the retrieved sound information.
 17. The simulated vehicle sound generator system of claim 1, where the vehicle is at least a partially-electric vehicle having an electric motor, and where the operating condition indicative of the speed of the vehicle comprises a road speed of the vehicle, where the simulated vehicle sound generation module is further executable to: receive a signal indicative of the road speed of the vehicle; determine an amount of current used for power regeneration of the vehicle; retrieve sound information for the one of the plurality of predetermined engine types corresponding to the road speed of the vehicle and the amount of current used for power regeneration; and adjust the sound signal based on the retrieved sound information.
 18. A method of generating simulated engine sounds in an audio system of a vehicle, the method comprising: receiving a current operating condition of the vehicle with a processor; selecting a first simulated gear from a plurality of respective simulated gears in response to the received current operating condition of the vehicle; generating an engine sound signal corresponding to a first operating range of the first simulated gear; driving at least one sound generation device of the vehicle to produce variable sound waves to simulate variable operation of a predetermined engine type along the first operating range of the first simulated gear; mapping a plurality of speed threshold values along the first operating range of the first simulated gear to a plurality of throttle positions; the processor determining a shift condition based on a current speed of the vehicle and a speed threshold value of the first simulated gear that corresponds to a current throttle position; selecting a second simulated gear from the plurality of simulated gears in response to the determined shift condition; adjusting the engine sound signal in response to the determined shift condition to correspond to a second operating range of the second simulated gear; and driving the at least one sound generation device of the vehicle to produce variable sound waves to simulate variable operation of the predetermined engine type along the second operating range of the second simulated gear.
 19. The method of claim 18, further comprising varying the engine sound signal when the vehicle is accelerating and decelerating.
 20. The method of claim 18, where the shift condition is a downshift condition and the speed threshold value is a downshift speed threshold value, where determining the downshift condition comprises determining that the current speed of the vehicle is less than the downshift speed threshold value of the first simulated gear corresponding to the current throttle position, and where the second simulated gear is a simulated gear lower than the first simulated gear.
 21. The method of claim 18, where the shift condition is an upshift condition and the speed threshold value is an upshift speed threshold value, where determining the upshift condition comprises determining that the current speed of the vehicle is greater than the upshift speed threshold value of the first simulated gear corresponding to the current throttle position, and where the second simulated gear is a simulated gear higher than the first simulated gear.
 22. A computer-readable storage medium encoded with computer-executable instructions, the computer-executable instructions executable with a processor, the computer-readable storage medium comprising: instructions to determine at least one operating condition of a vehicle; instructions to select a first sound based on the at least one operating condition of the vehicle, where the first sound is selected from a plurality of sounds, where each of the plurality of sounds comprises a simulated sound of an engine operating along an operating range of a respective simulated gear, and the first sound corresponds to a first simulated gear; instructions to generate an engine sound signal to drive at least one sound generation device in the vehicle to produce the selected first sound; instructions to detect a shift condition in response to an operating condition indicative of a speed of the vehicle reaching a variable threshold point corresponding to the first simulated gear, the variable threshold point being variable based on an operating condition indicative of a load of the vehicle; instructions to select a second sound in response to the detected shift condition, where the second sound is selected from the plurality of sounds and corresponds to a second simulated gear; and instructions to adjust the engine sound signal to drive the at least one sound generation device of the vehicle to produce the selected second sound.
 23. A computer-readable storage medium of claim 22 further comprising instructions to receive a user input representative of a desired engine type.
 24. A computer-readable storage medium of claim 22, further comprising instructions to retrieve the first sound from a sound library comprising the plurality of sounds.
 25. A computer-readable storage medium of claim 22, where the instructions to detect the shift condition comprise instructions to detect a reduction in a speed of the vehicle to within a predetermined vehicle speed range and to detect that a throttle position is within a predetermined throttle position range, where the second simulated gear is lower than the first simulated gear.
 26. A computer-readable storage medium of claim 22, where the instructions to detect the shift condition comprise instructions to detect an increase in a speed of the vehicle beyond the variable threshold point corresponding to a throttle position, where the second simulated gear is higher than the first simulated gear. 